Blind stitch sewing machine



June 6, 1939.

C. W. MUELLER BLIND STITCH SEWING MACHINE Filed June 19, 1937 9Sheets-Sheet l I N VEN TOR Ck ar/es l4. Mueller BY 1 ATTORNEY June 6,1939. c. w. MUELLER 2,161,527

BLIND STITCH SEWING MACHINE Filed June 19, 1957 9 Sheets-Sheet 2 June 6,1939. c; w MUELLER 2,161,527

BLIND STITCH SEWING MACHINE Filed June 19, 1937 9 Sheets-Sheet 3 Char/es"(Mae/lav June 6, 1939. c. w. MUELLER 2,161,527

BLIND STITCH SEWING MACHINE Filed June 19, 1937 9 Sheets-Sheet 4 June 6,1939. c w MUELLER 2,161,527

BLIND STITCH SEWING MACHINE Filed June 19, 1957 9 Sheets-Sheet 5 CharZesI4. Mae/la)" June 6, 1939. M L R 2,161,527

BLIND STITCH SEWING MACHINE Filed June 19, 1957 9 Sheets-Sheet 6gmwcnkvn Char/es W Muel/er June 6, 1939. c w L R 2,161,527

BLIND STITCH SEWING MACHINE Filed June 19, 1937 9 Sheets-Sheet 8 Char/esW Muel/er June 6, 1939. c. w. MUELLER BLIND STITCH SEWING MACHINE FiledJune 19, 1957 9 Sheets-Sheet 9 gvwc/wkvb Char/es )4. Ma q//er PatentedJune 6, 1939 UNITED STATES PATENT OFFICE BLIND STITCH SEWING MiCI-IINEApplication June 19, 1937, Serial No. 149,258

17 Claims.

This invention relates to new and useful improvements in sewing machinesgenerally, although more particularly to sewing machines of the blindstitch type.

In blind stitch sewing machines, such as is shown in each of my priorPatents 1,989,602, Jan. 29, 1935 and 2,018,186, Oct. 22, 1935, thereciprocatory ridge forming element is mounted directlybelow the needleon a work support which m is fulcrumed on a horizontal pivot located inrear of the needle path. The ridge forming element which in one form isa disc, is provided with relatively low and high peripheral portionswhich are alternately positioned in cooperative s relation with theneedle to form resultant anchor and skip stitches. The drivingconnections between the main shaft and the oscillatory shaft which isjournaled on the work support and which reciprocates the ridge formingelement, is such that when a seam or extremely thick layers of fabricsare fed over the element, the work support will be depressed and thedriving connections will cause the oscillatory shaft to rock and therebyshift the ridge forming element out of its true cooperative relationwith the needle with the result that one or more stitches will beimproperly positioned in the fabric or fabrics.

One of the important objects of this invention is to provide drivingconnections between the main shaft and the reciprocatory ridge formingelement operating shaft whereby the element will remain in its truecooperative relation with the needle when the pivoted work support isdepressed 5 and thereby insure the proper positioning of the stitches inthe fabric or fabrics.

Another object of the invention is to provide a main frame whichincludes a standard, a laterally extending upper arm and a forwardly and(m downwardly inclined arm, a reciprocatory needle and a presser footmounted on the front end of the forwardly extending arm, and a worksupport which is fulcrumed on a horizontal pivot located in front of theneedle path, whereby the 45 presser foot will remain at the same heightrelative to the operator and yet afford increased room under thelaterally extending arm for the passage of work when the work is beingfed rearwardly and also when the work is being removed 50 from themachine upon depression of the pivoted work support. 1

A further object of the invention is to provide a work clamp whichcooperates with the presser foot and which comprises two independentlymounted sections which are spring pressed upwardly for alternatecooperation with a top feed dog and the presser foot, together withmeans for varying the relative pressures of the sections against thefoot, whereby a body fabric and an overlying hem fold may be fedproperly.

A still further object of the invention is to provide a folder supportwhich is mounted on the main frame in front of the work support to swingabout a vertical pivot whenever it is desired to shift the foldersupport out of operative position and to provide means for elevating thesame during said swinging movement to insure the folder clearing theupper surface of the work support.

With these and other objects in view which will more fully appear, thenature of the invention will be more clearly understood by following thedescription, the appended claims, and the several views illustrated inthe accompanying drawings.

In the drawings:

Figure 1 is a top plan View of a machine constructed in accordance withmy invention,

Figure 2 is a right hand elevation thereof, the standard being shown insection,

Figure 3 is a front elevation thereof, the folder being omitted,

Figure 4 is a left end elevation thereof,

Figure 5 is a bottom plan View of the machine,

Figure 6 is an enlargedfragmentary-vertical section taken through thebase and work support substantially in the plane of oscillation of theneedle,

Figure 7 is an enlarged detail section showing a slight depression ofthe work support relative to the needle,

Figure 8 is an enlarged vertical section showing the work support in itslocked or normal position,

Figure 9 is a similar view but showing the work support in its unlockedor fully depressed position,

Figure 10 is a view showing the driving connections between the mainshaft and the oscillatory shaft which operates the ridge formingelement, the View indicating the limits of the oscillatory movements ofthe element when forming all anchor stitches,

Figure 10 is a View showing the corresponding position of the controllever,

Figure 11 is a view similar to Figure 10 but showing the limits ofoscillatory movements of the element when forming alternate anchor andskip stitches,

Figure 11 is a View showing the corresponding position of the controllever,

Figure 12 is a detail side elevation, partly in section, showing theadjustable tensioning means for a work clamp section,

Figure 13 is a perspective view of a portion of the main frame showingthe post which supports the work support,

Figure 14 is a perspective view of the left end of the work support,

Figure 15 is a vertical section taken through the pivot of the foldersupport,

Figure 16 is a plan view of the presser foot and showing the needle, thetop feed dog, the ridge forming element, and the work clamp, and

Figure 17 is a top plan view of the left end of the work support showingthe ridge forming element, the operating shaft therefor, and the workclamp.

Like reference numerals designate corresponding parts throughout theseveral figures of the drawings.

The sewing machine includes a main frame A which comprises a base 5, astandard 6, an arm I which extends laterally from the upper end of thestandard and terminates in a forwardly extending arm 8 which is inclineddownwardly and forwardly relative to the base, and a post 9 which isintegral with the base and is located at the front thereof and at theright of the arm 8, the post being inclined forwardly and having itsupper portion disposed in a vertical plane in front of the front end ofthe arm 8 and in a horizontal plane below said front end of said arm.

Rigidly fixed to the forward or free end of the arm 8, is a horizontalpresser foot B having a centrally located longitudinal opening or slot Iformed therein, the foot being forwardly and downwardly inclined in aplane disposed in parallelism to the major axis of said arm 8.

Journaled in the upper end of the standard 6 and in the arm I is a mainshaft I I, and journaled in the arm 8 and extending longitudinallythereof is an oscillatory needle shaft I2 having a needle arm I3 fixedto its front end. The needle shaft I2 is located directly above thepresser foot opening Ill and has its longitudinal axis in a downwardlyand forwardly inclined plane disposed in parallelism with the presserfoot. Attached to the needle a-rm I3 is a curved needle I4 whichreciprocates across the opening ID of the foot. The needle shaft I2 isoscillated from the main shaft II by connections such as is shown in myprior Patent 2,018,186 referred to above. A looper or spreader I5cooperates with the needle I4 in the usual manner to form single threadchain stitches, although any other type of complemental stitch formingmechanism may be employed if desired. The looper I5 is fixed to a looperrod I6 which is fulcrumed on a depending arm I! pivoted on a horizontalpin I8 mounted in the arm 8 and the looper rod is driven from the mainshaft II by the usual connections.

A work support C is clamped by'screws I9 to a horizontal pivot shaftjournaled in spaced bearings 2|, 2| formed in the post 9 of the mainframe. It will be noted that the pivot shaft 20 is disposed in a planeparallel to the main shaft II and that said pivot shaft is locatedconsiderably in front of the needle I4 as well as in front of thepresser foot 13. This work support C has its left end reduced to form ahorn 22 and projecting laterally from the outer end of the horn is arectangular frame 23 having an open top and bottom. This frame 23 islocated directly under the presser foot B and includes front and rearwalls 24, 25 and an end wall 26.

Operating in the presser foot opening II) for intermittently projectinga node of fabric upwardly into needle penetrating position, is a ridgeforming element D which in this instance consists of a disc fixed to anoperating shaft 21 which is journaled at the end in screw bearings 28,29, the screw bearing 28 being mounted in an opening 30 formed in theend wall 26 of the frame 23 and the screw bearing 29 being mounted in anopening 3| formed in a lug 32 which depends from the under side of theWork support C. The oscillatory operating shaft 27 is disposed in ahorizontal plane in parallelism not only with the main shaft II but alsowith the pivot shaft 20 of the work support. It will, therefore, be seenthat the work support C extends rearwardly from the pivot shaft 23 to apoint under the presser foot B and that this work support is capable ofswinging downwardly away from the presser foot or upwardly toward thesame. It will also be observed that the shaft 21 which operates theridge forming element D is disposed in rear of the pivot shaft 20 and ismovable upwardly and downwardly with the work support and consequentlywhen the work support is lowered the ridge forming element D will becorrespondingly lowered with respect to the path of the needle. Theridgeforming disc D is formed with a concentric periphery 33 and with aradial front edge 34, and a recess 35 is formed at their juncture, therecess forming a resultant step 36. It will be observed that theconcentric edge 33 and the step 36 form peripheral surfaces or portionsof different radii which are arranged in tandem, the portion 33constituting a high portion and the step 36 constituting a low portion.When the high portion 33 is positioned under the needle the latter willform resultant anchor stitches in the fabric or fabrics and when the lowportion 36 is positioned below the needle, the latter will form skipstitches in the fabric or fabrics. In other words, the eifective depthof needle penetration in the fabric or fabrics is constant when the highportion 33 is positioned below the needle but when the low portion 36 ispositioned below the needle the depth of needle penetration will bedecreased, as fully explained in my prior Patent 2,018,186 referred toabove.

An upwardly spring pressed work clamp E is mounted on the work support Cfor alternate cooperation with presser foot B and a 4-motion top feeddog 13. The top feed dog F operates in the opening I3 of the presserfoot B and is supported on the frame arm 8 and is operatively connectedto the main shaft 5! in the usual manner. This feed dog operates in rearof the needle path and cooperates with the work clamp E tointermittently feed the fabric rearwardly when the needle is out of saidfabric. The work clamp E cooperates with the bottom of the foot B toclamp the fabric therebetween during the idle motions of the feed dog Fwhereby said fabric will be held against the thrusts of the needle.

The work clamp E includes two separate clamping sections 31, 3'! whichare dipsosed side by side and extend longitudinally of the presser footfrom a point in front of the needle path to a point well in rearthereof, the front portions of the sections being recessed to receivethe ridge forming disc D and the rear portions of said sections beingdisposed in close relation below the presser foot opening I8 whereby thefeed dog F will cooperate with both sections. The work clamp sections 37are each pivoted as at 38 on the free end of ahori'zontal arm 39 of abell crank lever 46, the other arm. 4| of the lever projectingdownwardly in front of the front wall 24 of the rectangular frame 23 ofthe work support. These two levers 40 are arranged side by side and arefulcrumed at their angles on a common pivot shaft 4| which is disposedin parallelism with the disc operating shaft 21 and is mounted in abearing opening 42 formed in the horn 22 of thework support and securedtherein by a set screw 43. Associated with the vertical arm 4| ofeachlever is a coil spring 44, said spring extending through an openingformed in the front wall 24 of said frame 23, the front end of thespring being connected to the lever arm 4| and the rear end of thespring being connected to an adjustable tension screw 46 mounted in therear wall 25 of said frame 23. These two springs 44 function toyieldably urge the clamping sections 31 upwardly against the presserfoot B or top feed dog F. Adjustable stop screws 41, 41 have threadableengagements openings 48, 48 formed in the front wall 24 of the frame 23directly above the openings 45 for cooperation with the vertical arms4|, 4| of the bell crank levers 46, 46 and to thereby independently andvariably limit the upward movement of the clamping sections 31, 31.'These independent stops 41, 41 are very important in hemmingoperations. For instance, in hemming the bottom of a circular-cut skirt,there is considerable fullness in the hem fold, and this: fullness mustbe gathered in while the work is being fed through the machine. If thereis too much spring pressure applied to the right hand clamping section31 which engages the fabric directly below the hem fold, it becomes verydifficult for the operator to retard the base layer slightly in order toallow the top feed to fill or gather in the surplus material. Therefore,by providing the independently adjustable stops 41, 41 the pressure onthe clamping sections 31, 31 may be adjusted to suit working conditions.Furthermore, sometimes the above condition is reversed and a lesserpressure on the left hand clamping section 31 will be de sirable.

I The work support C is capable normally of a small free verticalmovement about its-pivot 20 to permit not only a variation in thethicknesses of materials being stitched but also to permit seams beingfed over the ridge forming disc D. To this end, the work support C isprovided with depending integral front and rear walls 49, 50respectively arranged on opposite sides of the disc operating shaft 21.A head 5| includes a horizontal attaching plate 52 and a dependingtubular neck 53 having an open lower end. The head 5| is rigidlyattached to the lower edges of the depending walls 49, 50 by screws 54,54. Mounted in said neck for vertical movements relative thereto is acore or support 55. A limiting screw 56 passes downwardly through anonthreaded opening 51 formed in the plate 52, the lower end of thescrew being threaded into the core and the head 58 of said screwcooperating with the plate 52 to limit the upward movement of the worksupport C relative to the core 55. The upper surface of the core isnormally spaced below the plate 52 and the upper portion of the core isreduced to form a resultantp eripheral recess for receiving a coilspring 59 which engages the bottom wall of the recess and the plate 52and functions to yieldably retain the work support C against downwardmovement relative to said core.

Thecore 55 is normally locked against vertical movements, but when thecore is moved vertically the work support C, the disc D, and the workclamp E are moved with it. The lower end of the core 55 is provided witha depending lug 66. A toggle is connected to the lug 68 and to the base5 of the main frame. The toggle includes a bell crank lever 6| whichincludes an upright arm 62 and a forwardly extending hori-' -zontal arm63.

The lower end of the arm 62 is fulcrumed on an eccentric 64 which isfixed to a horizontal shaft 65, the latter being disposed below the discoperating shaft 21 and in generally vertical alinement with said shaft21 and with the needle. The ends of the shaft 65 are journaled in thebase 5 below the upper surface thereof. A normally uprightly disposedlink 66 is pivotally connected at its upper end by a pin 61 to the lugand at its lower end by a pin 68 to the upper end of the toggle arm 62,the pin 68 being rigidly secured to the link 66 by a set screw 69. Acoil spring 10 is disposed around the projecting end of the pin 68, oneend of the spring being anchored in a transverse slot 1| formed in theouter end of the pin and the other end of the spring engaging under astop pin 12 fixed to thelink 66. The spring 16 functions to yieldablyretain the toggle elements 62, 66 in their longitudinally alined orlocked positions, as shown in Figure 8, and a stop shoulder 13 fixed tothe arm 62 cooperates with the stop shoulder 14 on the'bottom of thelink 66 in the manner illustrated in Figure 8 to prevent the toggleelements passing beyond their locked positions. It will be noted thatthe arm 62 and the link 66, when in their normal or locked positions,are in generally vertical or upright alinement, i. e., the pivots 61, 1|and are in alinement in a plane which is slightly inclined to thevertical, or in other words, in a plane at right angles to the plane ofthe foot B. A chain 15 which is adapted to be connected to a treadle orknee-press, has its upper end connected to the for'wardend of thehorizontal arm 63 of said bell crank lever. Thus upon operation of theknee-press or treadle the toggle will be broken and the support or core55 together with the work support C and parts mounted thereon, will bedepressed to permit the ready insertion or withdrawal of the material,and.- upon release of said knee-press or treadle, the parts will bereturned to their normal position by the spring 10. It will, therefore,be seen that when the toggle is in its locked or normal position, thework support C is capable of having a slight vertical movement againstthe tension of the spring 59 so as to permit various thicknesses offabrics and seams being fed through the machine.

In order to positively adjust the normal vertical I position of the worksupport C together with the disc D, and thereby set the machine formaterials of different thicknesses, I have provided a hand adjustingshaft 16 which is journaled in a bushing 11 mounted in a tubular bearingbracket 18 secured in an opening formed in the front wall of thestandard 6. A finger knob 19 is rigidly attached to the front end of theshaft 16 and a spring pressed pin 66 cooperates with the knob to retainthe shaft in any position of adjustment. Journaled on the bracket 18 isa worm wheel 8| which is in constant mesh with a worm 82 formed on theinner end of the shaft 16. Journaled in the base 5 is a horizontal rockshaft ,83 having a rock arm 84 fixed to its right hand end, said armbeing pivotally connected by a link 85 to the worm gear 8|. The otherend of the rock shaft 83 is provided with a rock arm 86 which ispivotally connected to the rear end of a rack bar 8'! which extendsforwardly along the base to a point below and in front of the eccentriccarrying shaft 65. The rack bar 81 is provided along its upper forwardedge with rack teeth 88 which engage the teeth of a pinion 89 fixed onsaid shaft 65. A disc 90 is journaled on the shaft 65 and is providedwith a pin 9I forming a support for the front end of said rack bar. A0011 spring 92 is connected at one end to the disc 90 and at its otherend to the base 5v and functions to urge the pin 9I upwardly whereby therack bar will be retained yieldably in engagement with the pinion 89. Ifdesired, a coil spring -92 may be provided and attached to the base 5and the bar 81 as shown in Figure 5 so as to be effective to constantlyurge the bar forwardly. It will, therefore, be seen that when the knob"I9 is rotated the rack bar 81 will be moved endwise, the shaft 65together with the eccentric 64 will be rotated, and the work supportwill be raised or lowered, depending on the direction of rotation of theknob.

The ridge forming element D is reciprocated from the main shaft II by atrain of mechanism including a manual control lever whereby either thehigh or low portions 33, 36 of the disc or element will be alternatelypresented to the needle to thereby form alternate anchor and skipstitches in the material or whereby thahighportion 33 only of the discor element will be successively presented to the needle to thereby formsuccessive anchor stitches in the material. To this end, a bell cranklever 93 is journaled on a horizontal axis 94 in the standard 6 andbelow the main shaft II. The bell crank lever 93 includes a forwardlyextending horizontal arm 95 which is connected by a link 91 to the main.shaft II through the medium of a 2-to-1 reduction gear coupling whichis indicated as a whole by the numeral 98 and which is fully shown anddescribed in my prior Patent 1,989,602 referred to above. The bell cranklever 93 includes a depending vertical arm 99 which is pivotallyconnected as at I to the rear end of a forwardly extending link IN. Ahorizontal shaft I02 is journaled in a base lug I03 at a point betweenthe pivot shaft 20 of the work support C and the disc operating shaft21, said shaft I02 being disposed in parallelism with said shafts 20 and21. Fixed to the right hand end of the shaft I 02 is an eccentric .pinI04 and a lever I05 is journaled intermediate its ends on said eccentricpin. The lower arm I06 of said lever is pivotally connected as at I01 tothe forward end of the link IM and the upper arm I08 of said lever ispivotally connected as at I09 to a rearwardly extending link IIO whichis pivotally connected at its rear end as at III to a depending rock armI I2 clamped to'the disc operating shaft 21. Fixed to the left hand endof the eccentric shaft I02 is an upwardly extending rock arm I I3 andpivotally connected to the upper end of said arm as at H4 is arearwardly extending link I I5, the rear end of said link beingpivotally connected as at 'I I6 to the lower end of a manually operablecontrol lever II! which is fulcrumed on the disc operating shaft 21 andhas its upper end provided with a finger-piece or knob I-I8 whichprojects through an opening II9 formed in the work support C. The knobIIO also projects upwardly through a slot I20 formed in a plate I2Imounted on the upper surface of the work support C.

It will be noted that the eccentric pin I04 constitutes a shiftablefulcrum for the lever I05 and that when the shaft I02 is oscillated bythe manually control lever II'I said fulcrum will be shifted eitherforwardly or rearwardly and the disc operating shaft 21 will beangularly shifted thereby, and consequently the disc D will be shiftedangularly with respect to the needle path. The driving connectionsbetween the main shaft II and the disc operating shaft 27 are such thatthe disc D will partake of a greater angular movement during alternaterearward strokes thereof and a lesser angular movement duringintermediate rearward strokes. Thus when the manually control lever II!is in the position shown in Figure 10 the high peripheral portion 33 ofthe disc D will be presented to the needle during successive rearwardmovements of the disc whereby successive anchor stitches will be formedin the fabric; and when the control lever is in the position shown inFigure 11 the high and low peripheral portions 33, 36 will bealternately presented to the needle whereby alternate anchor and skipstitches will be formed in the fabric. It will furthermore be observedthat when the work support C is in its normal or locked position saidsupport is capable of having a slight downward movement due to theintermediate spring 59, and that by reason of the lever I 05 beingdisposed between the pivot shaft of the work support and the discoperating lever 21 together with the link IIO which connects the lever I05 with the rock arm I'I2, this slight downward movement of the worksupport will maintain the low peripheral portion 36 of the disc D inproper cooperative relation to the needle path whenever said low portion36 is positioned in cooperative relation with the needle andconsequently the stitches will be properly positioned in the fabric.

As previously stated this machine is particularly adapted for blindstitching heins and therefore I have provided a support G for anadjustable hemmer H. The support G is mounted on the base '5 in front ofthe work support C and is adapted to swing about a vertical pivotwhenever it is desired to dispense with the folder. The support G isprovided at its right hand end with a depending bearing lug I22 having ahardened plate I23 attached to its lower end. A forwardly extendingbracket arm I24 is attached to the front edge of the base 5 and isprovided at its front end with a vertical bore or socket I25 in which ismounted the lower end of a tubular hinge pin I26, said pin being rigidlysecured to the bracket arm I24 by set screws I27. The hinge pin I26project's upwardly into a vertical bore or bearing opening I28 formed inthe bearing lug I22. A stop collar I29 is clamped to the hinge pin I26at a point between the bracket I24 and the'bearing lug I 22. The hingepin I26 is provided with upper and lower flanged caps I30, I3l whichrespectively engage the support G and the bracket I24, and a coil springI32 is disposed within the pin and has its ends connected to said capsfor yieldably retaining the folder support G against the stop collarI29. The upper surface of the folder support G is disposed below theforward end of the presser foot B in order to properly position thefolder, and consequently the upper surface of the support G is disposedin a horizontal plane below the upper surface of the work support C. Thehemmer H includes a base I33 which is attached to the folder support Gby screws I34. The left hand section I35 of the folder is laterallyadjustable and includes an arm I36 which is shiftable in guides I31, I31mounted on the base I33, said arm being disposed in parallelism with thedisc operating shaft 21. Furthermore, the arm I35 is disposed in ahorizontal plane below the upper surface of the work support C as shownin Figure 2, and consequently means are provided for automaticallyelevating the folder support G when the latter is swung forwardlywhereby the right hand end of the arm I36 will be elevated a sufficientdistance to clear the upper surface of the work clamp C. To this end,the stop collar I29 is provided with a cam I38 and the plate -I23 whichis attached to the bearing lug I22 is provided with a depending camfollower I39 which cooperates with the cam I38 to effect an elevation ofthe folder support G against the tension of the spring I32. A notch orseat I40 is formed in the upper surface of the stop collar I29 forreceiving the cam follower I39 when the folder support G is swung to itsinoperative or forward position and thereby frictionally retain saidsupport against accidental swinging movement.

It is of course to be understood that the details of structure andarrangement of parts may be variously changed and modified withoutdeparting from the spirit and scope of my invention.

I claim:

1. In a blind stitch sewing machine, the combination with a main frameincluding a base and a forwardly extending arm disposed in a plane abovethe base, of a main shaft journaled in the frame, a presser foot fixedto the front end of the arm and provided with an opening, a stitchforming mechanism mounted on the arm and including a needle mounted forreciprocations above the foot and across the opening therein, ahorizontal work support mounted on the base to swing upwardly anddownwardly relative to the foot and about a horizontal axis located infront of the needle, means for normally retaining the work supportyieldably against depression, a reciprocatory ridge forming elementoperating in the presser foot opening for projecting a ridge of fabricupwardly into needle penetrating position and movable upwardly anddownwardly with said work support, an oscillatory shaft journaled on thework support and disposed in parallelism with the axis thereof andoperatively connected to said element, and driving connections betweenthe main and oscillatory shafts for operating the latter and includingdevices for retaining the oscillatory shaft against angular movementupon depression of the work support.

2. In a blind stitch sewing machine, the combination with a main frameincluding a base and a forwardly extending arm disposed in a plane abovethe base, of a main shaft journaled in the frame, a presser foot fixedto the front end of the arm and provided with an opening, a stitchforming mechanism mounted on the arm and including a needle mounted forreciprocations above the foot and across the opening therein, ahorizontal work support mounted on the base to swing upwardly anddownwardly relative to the foot and about a horizontal axis located infront of the needle, means for normally retaining the work supportyieldably against depression, an oscillatory ridge forming discoperating in the presser foot opening for projecting a ridge of fabricupwardly into needle penetrating position and movable upwardly anddownwardly with said -work support, an oscillatory shaft journaled onthe work support and disposed in parallelism with the axis thereof andrigidly connected to said disc, and driving connections between the mainand oscillatory shafts for operating the latter and including devicesfor retaining the oscillatory shaft against angular movement upondepression of the work support.

3. In a blind stitch sewing machine, the combination with a main frameincluding a base and a forwardly extending arm disposed in a plane abovethe base, of a main shaft journaled in the frame, a presser foot fixedto the front end of the arm and provided with an opening, a stitchforming mechanism mounted on the arm and including a needle mounted forreciprocations above the foot and across the opening therein, ahorizontal work support mounted on the base to swing upwardly anddownwardly relative to the foot and about a horizontal axis located infront of the needle, means for normally retaining the work supportyieldably against depression, an oscillatory ridge forming discoperating in the presser foot opening for projecting a ridge of fabricupwardly into needle penetrating position and movable upwardly anddownwardly with said work support, said disc having high and lowperipheral work presenting portions arranged in tandem, an oscillatoryshaft journaled on the work support and disposed in parallelism with theaxis thereof and rigidly connected to said disc, and driving connectionsbetween the main and oscillatory shafts for operating the latter andincluding devices for retaining the oscillatory shaft against angularmovement upon depression of the work support, said driving connectionsperiodically presenting to the needle first one of said disc portionsand then the other to thereby vary the effective depths of the needlepenetrations.

4. In a blind stitch sewing machine, the combination with a main frameincluding a base and a forwardly extending arm disposed in a plane abovethe base, of a main shaft journaled in the frame, a presser foot fixedto the front end of the arm and provided with an opening, a stitchforming mechanism mounted on the arm and including a needle mounted forreciprocations above the foot and across the opening therein, ahorizontal work support mounted on the base to swing upwardly anddownwardly relative to the foot and about a horizontal axis located infront of the needle, means for normally retaining the work supportyieldably against depression, a reciprocatory ridge forming elementoperating in the presser foot opening for projecting a ridge of fabricupwardly into needle penetrating position and movable upwardly anddownwardly with said work support, an oscillatory shaft journaled on thework support and disposed in parallelism with the axis thereof andoperatively connected to said element, and driving connections betweenthe main and oscillatory shafts for operating the latter and includingdevices for retaining the oscillatory shaft against angular movementupon depression of the work support, said devices including asubstantially vertical lever fulcrumed on a horizontal axis locatedintermediate the work support pivot and the oscillatory shaft, a rockarm fixed to the oscillatory shaft, and a link connecting the upper endof the lever and the rock arm.

5. In a blind stitch sewing machine, the combination with a main frameincluding a base and a forwardly extending arm disposed in a plane abovethe base, of a main shaft journaled in the frame, a presser foot fixedto the front end of the arm and provided with an opening, a stitchforming mechanism mounted on the arm and including a needle mounted forreciprocations above the foot and across the opening therein, ahorizontal work support mounted on the base to swing upwardly anddownwardly relative to the foot and about a horizontal axis located infront of the needle, means for normally retaining the work supportyieldably against depression, an oscillatory ridge forming discoperating in the presser foot opening for projecting a ridge of fabricupwardly into needle penetrating position and movable upwardly anddownwardly with said work support, an oscillatory shaft journaled on thework support and disposed in parallelism with the axis thereof andrigidly connected to said disc, and driving connections between the mainand oscillatory shafts for operating the latter and including devicesfor retaining the oscillatory shaft against angular movement upondepression of the'work support, said devices including a substantiallyvertical lever fulcrumed on a horizontal axis located intermediate thework support pivot and the oscillatory shaft, a rock arm fixed to theoscillatory shaft, and a link connecting the upper end of the lever andthe rock arm.

6. In a blind stitch sewing machine, the combination with a main frameincluding a base and a forwardly extending arm disposed in a plane abovethe base, of a main shaft journaled in the frame, a presser foot fixedto the front end of the arm and provided with an opening, a stitchforming mechanism mounted on the arm and including a needle mounted forreciprocations above the foot and across the opening therein, ahorizontal work support mounted on the base to swing upwardly anddownwardly relative to the foot and about a horizontal axis located infront of the needle, means for normally retaining the work supportyieldably against depression, an oscillatory ridge forming discoperating in the presser foot opening for projecting a ridge of fabricupwardly into needle penetrating position and movable upwardly anddownwardly with said work support, said disc having high and lowperipheral work presenting portions arranged in tandem, an oscillatoryshaft journaled on the work support and disposed in parallelism with theaxis thereof and rigidly connected to said disc, and driving connectionsbetween the main and oscillatory shafts for operating the latter andincluding devices for retaining the oscillatory shaft against angularmovement upon depression of the work support, said driving connectionsperiodically presenting to the needle first one of said disc portionsand then the other to thereby vary the effective depths of the needlepenetrations, said devices including a substantially vertical leverfulcrumed on a horizintal axis located intermediate the work supportpivot and the oscillatory shaft, a rock arm fixed to the oscillatoryshaft, and a link connecting the upper end of the lever and the rockarm.

'7. In a blind stitch sewing machine, the combination with a horizontalpresser foot having an opening, an intermittent top feed dog operatingin said opening, separate work clamp sections located below the foot foralternate cooperation with the feed dog and the foot, separate springmeans for pressing said clamp sections upwardly into said cooperativerelation with said feed dog and foot, and means for varying the pressureof one of said spring means.

8. In a blind stitch sewing machine, the cormbination with a horizontalpresser foot having an opening, an intermittent top feed dog operatingin said opening, separate work clamp sections located below the foot foralternate cooperation with the feed dog and the foot, separate springmeans for pressing said clamp sections upwardly into said cooperativerelation with said feed dog and foot, and separate means for varyingindependently the pressures of said separate spring means.

9. In a blind stitch sewing machine, the combination with a horizontalpresser f'oot having an opening, an intermittent top feed dog operatingin said opening, a support located below the foot, separate work clampsections mounted on the support for alternate cooperation with the feeddog and the foot, springs respectively interposed between said sectionsand the support for pressing said sections upwardly into saidcooperative relation with said feed dog and foot, and means locatedbetween the support and one of said sections for varying the pressure ofthe associated spring.

10. In a blind stitch sewing machine, the combination with a horizontalpresser foot having an opening, an intermittent top feed dog operatingin said opening, a support located below the foot, separate work clampsections mounted on the support for alternate cooperation with the feeddog and the foot, springs respectively interposed between said sectionsand the support for pressing said sections upwardly into saidcooperative relation with said feed dog and foot, and separate meanslocated between the support and the sections for varying independentlythe pressures of the associated springs.

11. In a blind stitch sewing machine, the combination with a horizontalpresser foot having an opening, an intermittent top feed dog operatingin said opening, a support located below the foot, separate bell cranklevers fulcrumed on the support to swing about a horizontal axis, eachlever including a horizontal arm and a depending vertical arm, workclamp sections respectively pivoted on the horizontal arms for alternatecooperation with the feed dog and the foot, coil springs respectivelyconnecting the vertical arms of the levers and the support for pressingsaid sections upwardly into said cooperative relation with said feed dogand foot, and a stop screw threadably mounted in the support forengagement by the vertical arm of one lever to variably limit thepressure of the associated spring.

12. In a blind stitch sewing machine, the combination with a horizontalpresser foot having an opening, an intermittent top feed dog operatingin said opening, a support located below the foot, separate bell cranklevers fulcrumed on the support to swing about a horizontal axis, eachlever including a horizontal arm and a depending vertical arm, workclamp sections respectively pivoted on the horizontal arms for alternatecooperation with the feed dog and the foot, coil springs respectivelyconnecting the vertical arms of the levers and the support for pressingsaid sections upwardly into said cooperative relation with said feed dogand foot, and stop screws threadably mounted in the support forengagements by the vertical arms of said levers to variably andindependently limit the pressures of the associated springs.

13. In a sewing machine, the combination with a base and a laterallyextending arm, of a presser foot mounted on the free end of said arm, areciprocatory needle supported on the arm above the foot, a work supportmounted on the base and having a portion underlying the foot, a foldorsupport located in front of the work support and mounted on a verticalaxis to swing forwardly from an operative position to an inoperativeposition, and a folder mounted on said folder support for directing afolded fabric to the needle when said support is in its operativeposition.

14. In a sewing machine, the combination with a base and a laterallyextending arm,of a presser foot mounted on the free end of said arm, areciprocatory needle supported on the arm above the foot, a work supportmounted on the base and having a portion underlying the foot, a foldersupport located in front of the work support and mounted on a verticalaxis to swing forwardly from an operative position to an inoperativeposition, the upper surface of the folder support be ing normallydisposed in a lower horizontal plane than the upper surface of the worksupport, and a folder mounted on said folder support for directing afolded fabric to the needle when said support is in its operativeposition, said folder support being elevated automatically when swungfrom its operative position to its inoperative position whereby thefolder will clear the work support.

15. In a sewing machine, the combination with a base and a laterallyextending arm, of a presser foot mounted on the free end of said arm, areciprocatory needle supported on the arm above the foot, a work supportmounted on the base and having a portion underlying the foot, a postmounted on the base in front of the work support, a bearing collar fixedto the post and provided with a cam, a folder support mounted on saidpost to swing forwardly from an operative position to an inoperativeposition, the upper surface of the folder support being normallydisposed in a lower horizontal plane than the upper surface of the worksupport, a folder mounted on said folder support for directing a foldedfabric to the needle when said support is in its operative position, anda cam follower fixed to the foldi support in its inoperative position.

er support for cooperation with said cam whereby the folder support willbe elevated and the folder will clear the work support when the foldersupport is swung to its inoperative position.

16. In a sewing machine, the combination with a base and a laterallyextending arm, of a presser foot mounted on the free end of said arm, areciprocatory needle supported on the arm above the foot, a work supportmounted on the base and having a portion underlying the foot, a postmounted on the base in front of the work support, a bearing collar fixedto the post and provided with a cam, a folder support mounted on saidpost to swing forwardly from an operative position to an inoperativeposition, the upper surface of the folder support being normallydisposed in a lower horizontal plane than the upper surface of the worksupport, a folder mounted on said folder support for directing a foldedfabric to the needle when said support is in its operative position, acam follower fixed to the folder support for cooperation with said camwhereby the folder support will be elevated and the folder will clearthe work support when the folder support is swung to its inoperativeposition, and spring means between the post and the folder support foryieldably retaining the cam follower in engagement with the cam.

1'7. In a sewing machine, the combination with a base and a laterallyextending arm, of a presser foot mounted on the free end of said arm, areciprocatory needle supported on the arm above the foot, a work supportmounted on the base and having a portion underlying the foot, a postmounted on the base in front of the work support, a bearing collar fixedto the post and provided with a cam, a folder support mounted on saidpost to swing forwardly from an operative position to an inoperativeposition, the upper surface of the folder support being normallydisposed in a lower horizontal plane than the upper surface of the worksupport, a folder mounted on said folder support for directing a foldedfabric to the needle when said support is in its operative position, anda cam follower fixed to the folder support for cooperation with said camwhereby the folder support will be elevated and the folder will clearthe work support when the folder support is swung to its inoperativeposition, said collar being provided with a notch for receiving the camfollower to retain the folder CHARLES W. MUELLER.

